In the field of semiconductor devices, microelectromechanical systems (MEMS) and the like, miniaturization is increasingly demanded, and a photo-nanoimprinting technique is attracting attention, accordingly.
In the photo-nanoimprinting technique, a mold having a fine relief pattern on the surface thereof is pressed against a substrate to which a photocurable composition (resist) has been applied, and the photocurable composition is cured in this state. Thus, the relief pattern of the mold is transferred to a cured product of the photocurable composition to yield a pattern on the substrate. The photo-nanoimprinting technique enables a fine structure of the order of several nanometers to be formed on a substrate.
In a photo-nanoimprinting technique, first, a resist is applied to the region on a substrate to which a pattern will be formed (application step). Subsequently, the resist is formed into a pattern in a mold having a pattern (mold contact step). Then, the resist is cured by being irradiated with light (irradiation step), and separated from the mold (mold-releasing step). Through these steps, a resin pattern (photo-cured film) having a specific shape is formed on the substrate.
The cured product pattern, or photo-cured film, formed on the substrate by the photo-nanoimprinting technique may be used as a mask for processing a base substrate by dry etching. In this operation, the photocurable composition is desirably resistant to dry etching from the viewpoint of processing the base substrate with a high yield.
The resistance to dry etching (hereinafter referred to as dry etching resistance) of the photocurable composition depends on the constituents of the photocurable composition and the proportions thereof. The viscosity of the photocurable composition also depends on the constituents of the photocurable composition and the proportions thereof.
Viscous photocurable compositions are slow to fill the mold. More specifically, such a photocurable composition is slow to spread over the substrate when applied to the substrate, or slow to fill the recesses in the fine relief pattern in the mold after being brought into contact with the mold. Thus, the use of a viscous photocurable composition results in a low productivity in forming a cured product pattern by photo-nanoimprinting.